godley



C. E. GODLEY Dec. 22, 19-25- REFLECTOR ori ina Filed May 8. 19,2 2Sheets-Sheet 1 G imu ESQ mu C. E. GODLEY Dec. 22, 925- REFLECTOROriginal Filed May a. '1922 2 Sheets-Sheet 2 3 LT l H I I I PatentedDec. 22, 1925.

w UNITED STATES- 1,566,590 PATENT, OFFICE.

CHARLES E. GODLEY, OE DETROIT, MICHIGAN, ASSIGNOR TO EDMUNDB AND JONESCORPORATION, 01 DETROIT, MICHIGAN, A. CORPORATION OF NEW YORK. I

anrmc'ron.

Original application filed Kay 8, 1822, Serial 'lIo. 559,204. Iiivided.and this application filed Kay 8, 10M.

' Serial 1T0. 710,770.

To all whom it only concern:

Be it known that I, GHAaLEs E. YGODLEY,

a citizen of the United States, and residing at Detroit, in the countyof Wayne and State of Michiga'n, have invented a new and ImprovedReflector, of which the following is a specification.

This invention relates to the construction of the reflectors ofprojecting lamps, especially the headlamps of motor vehicles of thetypes shown in my co-pending application, Ser. No. 559,204, filedMa-y 8,1922, of which this is a division, and its object is to so divide thereflector into sections that the rays'of light will be projected upon aclearly defined limited area and in part concentrated upon a restrictedportion of such area.

Lamps equipped with the well known parabolic reflectors cannot producethis effect for when such lamps are so positioned that the concentratedlight properly illuminates the roadway sufficiently far in advance topermit the driver to avoid obstructions,

the roadway nearer the vehicle is left dark, or too much light isprojected upward and sidewise where it is liable to blind oncomingdrivers and pedestrians.

These objections are overcome by deforming a reflector of substantiallyparaboloidal shape so that different portions thereof will project beamswhose cross-sections are similar in shape but difi'erent'in size, and sothat the larger and milder beam will afford a general road illuminationof considerable spread while the more concentrated beam will afford a.driving light illuminating a narrower stretch of road for a considerabledistance ahead of the vehicle.

My invention therefore consists .in deforming a substantially parabolicreflector so that it will project beams of greater width than height andin a reflector of this character which can be manufactured atapproximately the same cost as an ordinary paravboloidal reflector andin which the special deformations will not interfere with the usualmachine polishing of the reflecting surface.

of the general araboloidal form of the re fiector farther t an itslateral edges. I vary the depth of the convexity of the crosssection orthe width of the panels according to the desired spread ofthe projectedbeam, and vary the relation of the central lines of the panels to .thevertical plane passing through the focal axis of the reflector accordingto the directions in which the beam is to be ex anded.

The cross-section 0 each panel on a line radial to the inner edge ofsaid panel is the same as a horizontal cross-section of the same widthof a determinin center of this cross-section o the determining parabolabeing in a line assing through the focal center of both bodies andthrough substantially the middle of said cross-section of said panel,but reversed. This rule holds with reflectors having panels, all ofwhose sides are parallel and vertical and with reflectors divided intopanels of irregular form so long as the cross sections of these panelsare tiltedinto the lanes in which the light is to be spread. or example,if the central lines of the panels in a headlight reflector having ahorizontal axis were all in vertical planes, the beam of the reflectorwould be expanded from circular to elliptical cross-sections with themajor axis of the ellipses horizontal. If the ends of such generallyupright panels curve slightly toparabola, the.

ward or away from a vertical plane, the

transverse sections of a parabola of a much longer focus for the moreconcentrated light. Byusing the longer-focus transverse sections, thepanels can be of any predetermined width, the spread of light beingdetermined by the focal length of the parabola used in determining thetransverse. sections of the panels.

By using transverse parabolic sections in the-panels I find that thelight rays reflected from each panel diverge equally from i the axis ofthe reflector, the rays from each panel covering substantially theanticipated field of light of the different sections.

. I have also found that if the convexity of each panel is just thereverse of the'normal parabolic section for the same ortio-n of thereflector, using narrower pane s for greater concentration and widerpanels for the more diffused light, that the width of panels aredetermined by the width of spread desired in the projected fields.

In the accompanying drawings Fig. 1 is v a, front elevation of areflector embodying the present invention. Fig. 2 is a section on theline 2--2 of-Fi 1. Fig. 3 is a diagram illustrating the'lig t raysprojected by the Figs. 1, 2, 1 and 2 are diagrams showing the method fordetermining I the proper cross sections of the paraboloidal panels. 1 ISimilar reference characters refer to like parts throughout the severalviews.

The reflector 1 is generally'parabolic in form. If a light bulb could,be made with a filament with substantially no dimensions and thisfilament mounted at the focus of the reflector, then this reflector, ifa perfect parabola, would project a beam of light of the diameter of thereflector. The filaments of light bulbs are, however, of considerablesize so that the light projected is in the form of a cone whose surfaceis somewhat indefinite.

After the parabola has been formed and polished, it is placed betweenproper dies and its surface is deformed so as to be divided into panels3 and 4, those next to central aperture 2 of the reflector in Figures 1and 2 being 'narrower than those farther away. I,

Each of these panels has substantially parallel sides and these sidesare convex toward the central opening 2. I have shown the lateralcurvaturesof these panels to be substantially uniform but this is notnecessary as the curvature of the ends of these panelsis suflicient toproject li ht toward the corners of the main pro ected eld so thatinstead of a circular field of light, this refleigor projects asubstantially rectangular fie o The desired width of the panels beingfixed, the exact cross-sections of the panels ma be determined after themanner shown in igures 1 to 2 inclusive. For any given portion of thepanel 3 shown in Figure 2, I first determine the center G of thecrosssection of the corresponding part of the original ortrueparaboloidal surface 1, as

shown in Figure 1*. I then draw a line from which the focal line F Gintersects the determining parabola indicates the central polnt of asmall sectlon of the parabola l which has the proper curvature for thedesired panel cross-section. If this determining parabola is of greaterfocal length than the parabola 1 (which is part of the true paraboloidalsurface from which the reflector is to be formed and which it will stillapproach rather closely when finished) this curvature is reversed asshown in Figures 1" and 1.

Cross-sections of the panel 3 at other points are similarly determined,each being taken radially to the inner edge of the panel as shown by thelines K in Figure 2 This insures. a panel which efl'ects an unusuallyuniform distribution of light. Owing to the resulting uniform density ofthe projected beam and of the beam-widening effect due to the edgewisecurving of the panels, they cooperate in projecting a beam of approximately rectangular cross-section with its upper and lower borderssubstantially parallel to the plane of the line 3 in Fig. 2 The lines Kindicate how the rays of light are deflected up and down so as toproceed along lines substantially at right angles to the border lines ofthe panels at the points of reflection.

Each of the panels resents a transversely convex surface to-war theplane of the open end of the reflector and the curvature of such panelat every point in its length is desirably the same as a horizontalcross-section of the determining reflector taken in a line passingthrough the focal points of both reflectors, reversed and placed so asto coin cide with the normal paraboloidal reflector surface at the edgesof each panel and tilted into the planes in which the light is to bespread. The curvature of each panel is therefore greatest at thehorizontal diameter of the reflector.

This parabolic transverse curvature of the several panels enables me todeterminethe exact field to be illuminated by the rays reflected by eachpanel, and the rays of the light from each panel are projected so as tofall evenly upon the entire predetermined field of illumination, thatis, illuminate evenly the field on both sides of the axis of thereflector. The angle of diffusion therefore of the rays reflected by anyparticular panel depends upon the focal length of the deterbe noticedthat each of the panels is of subcorners of this field. This results ina field of illumination which is practically rectangular.

The panels nearer the central 0 ening of the reflector are made narrowerin proportion to their depth than those farther away which results inthe rays projected b :the'

comparatively more shallow panels eing concentrated on a more limitedfield than those projected by the comparatively deeper panels. Thisvariation in transverse curva-- tu're of the panels may be gradual orabrupt. The central portion of the illuminated field will therefore bebrighter than the outer portions and this area of more intenseillumination may be moved up ordown in the field of milder illuminationby tilting the general focal axis of the outer more shallow panels. Theouter portions of the reflector approach more nearlya true parabola andthe light projected thereby is therefore more concentrated. I prefer totilt these panels about one degree upward so that the area of intenseillumination will be positioned at the upper portion of the less intensebut larger field.

Fig. 3 is a diagram showing the proportionate illuminationof a field bymeans of a, reflector of this character, the field being divided asshowninto eighty squares, and thelength of the sides of the squaresequally approximately one degree of are on a spherical surface whose.radius is one hundred feet, the general focus of the reflector being atthe center of this spherical surface. With the source of illumination atthe focal point 6, Fig. 2, some of the rays of reflected light areprojected by each of the narrow and deeply curved panels 4 over asurface extending from one vertical line 8 to the other and betweenhorizontal lines 0 and 4.

The side panels 3 are wider and shallower so that the light reflected bythese panels is diffused to a much less extent, both horizontally andvertically, for the'reason that they approach more closely to the trueparabolic reflector. Now by tilting those portions of the reflectorwhich embody the panels 3, through an angle of about one degree, so asto swing the axis 6-7 up above the axis 68 of the remaining portion ofthe reflector, the area of most intense illumination is moved up.

WVhere an automobile headlight is less than four feet above the roadway,and the" rays of light strike the roadway about two hundred feetfromthe-vehicle, the width of the area of intense illumination should bethat of the roadway and it may extend about one hundred feet toward thevehicle; The

area of less intense illumination derived from the more convex panelsWlll extend over-this same distance and in addition thereto, extend overspace on each side'of the more intense field andbetween it and thevehicle. 4

' The comparative widths of these panels and their curvatures relativeto the central vertical plane of the. reflector may. all be changed bythose skilled in the art without departure from the spirit of myinvention as set forth in the following claims.

I claim 1. A paraboloidal reflector composed of a group of panels oneach side of the center of the reflector, the panels on each side of thecenter ofthe reflector being substantially .parallel to each other, eachpanel beingt transversely convex toward the general focus of thereflector and 1ts transverse curvature at each point being the same asthat of the general curve of a parabola at that point but 111 theopposite direction, the edges of the panel being convex toward thegeneral axis of the reflector.

2. A paraboloidal reflector composed of a group 0 panels on each side ofthe center of ture at each point being the same as that of the generalcurve of a parabola at that point but in the opposite direction, theedges of the panels being convex toward the general axis of thereflector, the panels on each sideof the reflector being divided intoinner and outer groups, the panels of oneof the groups on each sidebeing deeper in proportion to their width than those of the other groupon that side so as to produce a greater diffusion of light.

3. A paraboloidal reflector composed of'a group of panels on each sideof the center of the reflector, the panels on. each side of the centerof the-reflector being substantially parallel to each other, each panelbeing transversely convex toward the general focus of the reflector andits transverse curvature at each point being the same as that of thegeneral curve of a parabola at that point but in the opposite direction,the edges of the panels being, convex toward the general axis of thereflector,-the panels on each side of the reflector being divided intovinner and outer groups, and the general focal axis of the inner groupsbeing at an angle to the general focal axis of the outer groups.

4. A paraboloidal reflector composed of a group of anels on each side ofthe center of the re ector, the panels on each side of the center of thereflector being substantlally parallel to each other, each panel beingtransversely convex toward the general focus of the reflector and itstransverse curvature at each point being the-same as that of the generalcurve of a parabola at that point but in the opposite direction, theedges of the panels being convex toward the general axis of thereflector, the panels on each side of the reflector being divided intoinner and outer groups, the panels of the inner grou sbeing deeper inproportion totheir wi th than those of the outer groups, and the generalfocal axis of the inner groups being at an angle to the general focalaxis of the outer groups but in the same plane. 4 i

5. A parab 'loidal reflector'composedof a group of panels on each sideof the center of the reflector, the panels on each side of the center ofthe reflector being substantially.

parallel to each other, each panel being transversely convex toward thegeneral focus of the reflector,-the edges of the panels being convextoward an axial plane of, the .reflector.

6. A paraboloidalreflector composed of a group of panels on each side ofthe/center of the reflector, the panels on each side of the center ofthe reflector being substantially parallel to each other, each panelbeing transversely convex toward the general focus of the reflector, theedges of the panels being convex toward the general axis of thereflector, the panels on each side of the reflector being divided intoinner and outer groups, the panels of the inner groups being 'deeper inproportion to their width than those of the outer roups so as to producea greater lateral dlusion of light.

7. A paraboloidal reflector composed of a group of panels on each sideof the center of the reflector, the panels on each side of the center ofthe reflector being substantially parallel to each other, each panelbeing transversely convex toward the eneral focus of the reflector, theedges'of t e panels being convex towardthe general axis of thereflector, the panels on each side of the refiector bein divided intoinner and outer roups, angfthe'general focal axis of the inner groupsbeing at an angle to the general 7 focal axislof the outer'groups. Aparaboloidal re ector composed of a group of panels on each side of thecenter of the reflector, the panels on each side of the center of thereflector being parallel to each 1 other, each panel being transverselyconvextoward the general focus of the reflector, the middle portions of.the panels being "nearer the general vertical plane of the re flectorthan their ends, the panels nearer said plane being narrower and moreconvex in transverse-cross section ther away from said planet 9. Aparaboloidal, reflector composed of a than those fargroup of panels oneach side of the center of the reflector, the panels on each side of thecenter'of the reflector being substantially parallel" to each other,each panel being transversely convex toward the general focus of thereflector, the edges of the panels being panels all being in a commonparaboloidal surface.v Y

" 5 ,CHARLES E. GODLEY.

